A display device equipped with a display panel, such as a liquid crystal display device equipped with a non-light-emitting liquid crystal display panel, is typically provided with an illumination device, which is a backlight unit in this case, for supplying light to the liquid crystal display panel. Such a backlight unit is equipped with a light guide plate that converts light to planar light so as to produce planar light that corresponds to the liquid crystal display panel having a planar shape.
As shown in FIG. 10, a backlight unit described in Patent Document 1, for example, includes light guide plates 111 (111α, 111β) that receive light from a light emitting diode (LED) 122 and that convert the light to planar light by internal multiple reflection. The light travelling from these light guide plates 111α and 111β enters a liquid crystal display panel 149 having a planar shape. The member indicated by the reference character 135 is a backlight chassis 135 that houses the light guide plates 111α and 111β.